Air seeders typically include an implement frame mounted on wheels, with a plurality of furrow openers mounted on the frame. The furrow openers can be moved from a raised non-operative position to a lowered operating position where the furrow openers engage the ground and create furrows. Agricultural products such as seed and various types of fertilizer are carried in separate tanks which can be mounted on the implement frame or on a cart towed along with the implement frame.
Metering devices dispense products from the tanks into one or more air streams that carry the products through a distribution network of hoses and manifolds to the furrow openers where same are deposited in the furrows. Most modern air seeders have furrow openers that deliver seed to seed furrows and fertilizer to separate fertilizer furrows. These may be totally separate furrow openers mounted on separate shanks, such as mid row fertilizer banding furrow openers which are remote from the seed furrow openers, or combination furrow opener where a single shank supports a furrow opening tool that makes one furrow for seed and a separate furrow for fertilizer. There are also then two separate distribution networks, one delivering product from selected tanks to the seed furrows, and one delivering product from selected tanks to the fertilizer furrows.
The terms “seed” and “fertilizer” are not meant restrictively, since in many cases some fertilizer is metered into the air stream carry the seed, and also in some instances it may be that fertilizer may be directed into the “seed” furrows, and vice versa if conditions warrant it. The terms “seed” and “fertilizer” are simply convenient to differentiate the two separate “runs” or air streams. Basically in an air seeder it is desirable to be able to direct agricultural product from any of the tanks into any of the available air streams. Similarly the term “seeded area” as used herein may refer to an area where any desired agricultural products have been applied.
In one type of distribution network for an air seeder, the air stream carries the product from a feeding mechanism through a primary hose to a manifold where the air stream and product is divided and directed into multiple secondary hoses connected to the manifold outlet ports which deliver the product to the furrow openers. In some distribution networks each secondary hose connects into a further manifold and the air stream is divided again into further final hoses leading to each furrow opener. In other air seeders each distribution network comprises simply a conduit that leads directly from a feeding mechanism to each furrow opener. In all such air seeders there is a delay period between the time when the feeding mechanism starts to feed product into the distribution network and the time when the product arrives at the furrow openers. In addition the delay period is not the same for all furrow openers because the delivery network is longer for some furrow openers, for example furrow openers on outer ends of the implement, than for others, such as those closer to the middle of the implement.
When a seeding implement is operated in a field it is necessary to stop the product application from time to time, such as when turning at headlands, to avoid double application of product, commonly referred to as overlap. When moving the implement back toward an unseeded field area, the application must be started again. When it is desired to apply product, the feeding mechanism is activated to dispense product into the input end of the distribution network where the air stream carries it to the furrow openers. There is a start delay period between the time the feeding mechanism starts dispensing and the time the product reaches the furrow openers. Similarly when it is desired to stop applying product, the feeding mechanism is deactivated and stops dispensing product into the distribution network, however the product already in the distribution network continues to flow to the furrow openers and there is a stop delay period between the time the feeding mechanism stops dispensing and the time the last of the product reaches the furrow openers and product placement in the furrows stops.
The delay periods can vary significantly with different types of product and product volumes, velocity of the air stream, and like factors, and so should be reset when these factors are changed for different crops, fertilizer rates, and the like.
These delay periods are determined generally by timing the period between starting or stopping the feeding mechanism and seeing product flow at the furrow openers on the implement start or stop. In conventional operations the operator will estimate the point at which the feeding mechanism should be turned off when approaching a headland, or turned on when moving from a seeded to an unseeded area.
In modern operations computerized external guidance systems, using global positioning satellites (GPS) or more localized broadcasting towers or the like, determine the air seeder location, map the field, and determine where overlap areas will occur, and start and stop the supply of products to the furrow openers accordingly. The delay period is then entered into the external guidance system which determines the field locations where the feeding mechanism is turned on or off by calculating the distance travelled during the delay time. Because of the irregular pattern of many fields, and the unequal lengths of the distribution networks, an added safety factor is usually used to ensure against missing product application on any field areas where same is desired.
In conventional air seeders product application is started and stopped across the entire width of the implement, and the feeding mechanism is generally a metering device dispensing product from tanks. In order to reduce overlap in wide air seeders it is desirable to be able to shut off the supply of product to laterally distinct sections of the air seeder, as described generally in U.S. Pat. No. 8,578,870 to the present inventor Beaujot, the contents of which is hereby incorporated by reference. These sectional control systems use a computerized external guidance system to start and stop the supply of products to each section accordingly. Control of the flow of product into separate section distribution networks connected to each section can be provided by various feeding mechanisms such as manifold valves, gated meters, individual metering devices for each section, and the like as are known in the art.
In one example of sectional control, the furrow openers in a laterally distinct section of the air seeder are fed product by a single manifold. At all times during operation an air stream flows through the primary conduit from the metering device to the manifold and from the manifold through the secondary conduits to the furrow openers.
Each manifold is fed product by a separate metering device, such as for example is disclosed in United States Published Patent Application Number 2012/0279430 of the present inventor Beaujot. When it is desired to apply product to the section, the metering device is activated to dispense product into the air stream where it is carried to the manifold and then to the furrow openers.
In other systems, for example as disclosed in U.S. Pat. No. 7,555,990 to Beaujot, the feeding mechanism is a manifold with valves on the output ports which are opened and closed to start and stop product flow to the furrow openers, and the delay time occurs between the time the valve feeding product to a section is opened or closed, and the time product flow starts or stops at the furrow openers.
Thus when setting up a computer controlled sectional control system it is necessary to set start and stop delay periods in the system for each section to avoid overlap and areas where product application is missed. When the guidance system determines that a section must start or stop dispensing at a certain location, it must start or stop the feeding mechanism before the furrow openers reach that location to account for the start and stop delay periods. Currently these delay periods are set generally by timing the period between starting or stopping the meter and seeing product flow at the furrow openers in the section start or stop. Setting the delay periods is complicated by the fact that some sections will be farther from the feeding mechanisms than others due to the configuration of the distribution networks.